Diverse Profile of Fermentation Byproducts From Thin Stillage

Author(s)

Fortney, Nathaniel W. ^[1] ; Hanson, Nathaniel J. ^{[1, 2]} ; Rosa, Paula R. F. ^{[1, 3]} ; Donohue, Timothy J. ^{[1, 4]} ; Noguera, Daniel R. R. ^{[1, 5]}

Affiliation

^[1] Univ Wisconsin Madison, Great Lakes Bioenergy Res Ctr, Madison, WI 53706 - USA

^[2] Wisconsin Youth Apprenticeship Program, Dept Workforce Dev, Madison, WI - USA

^[3] Univ Fed Sao Carlos, Dept Chem Engn, Sao Carlos - Brazil

^[4] Univ Wisconsin Madison, Dept Bacteriol, Madison, WI 53706 - USA

^[5] Univ Wisconsin Madison, Dept Civil & Environm Engn, Madison, WI 53706 - USA

• Document type: Journal article
• Source: FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY; v. 09, JUL 15 2021.
• Web of Science Citations: 0

Abstract

The economy of biorefineries is influenced not only by biofuel production from carbohydrates but also by the production of valuable compounds from largely underutilized industrial residues. Currently, the demand for many chemicals that could be made in a biorefinery, such as succinic acid (SA), medium-chain fatty acids (MCFAs), and lactic acid (LA), is fulfilled using petroleum, palm oil, or pure carbohydrates as raw materials, respectively. Thin stillage (TS), the residual liquid material following distillation of ethanol, is an underutilized coproduct from the starch biofuel industry. This carbon-rich material has the potential for chemical upgrading by microorganisms. Here, we explored the formation of different fermentation products by microbial communities grown on TS using different bioreactor conditions. At the baseline operational condition (6-day retention time, pH 5.5, 35 degrees C), we observed a mixture of MCFAs as the principal fermentation products. Operation of a bioreactor with a 1-day retention time induced an increase in SA production, and a temperature increase to 55 degrees C resulted in the accumulation of lactic and propionic acids. In addition, a reactor operated with a 1-day retention time at 55 degrees C conditions resulted in LA accumulation as the main fermentation product. The prominent members of the microbial community in each reactor were assessed by 16S rRNA gene amplicon sequencing and phylogenetic analysis. Under all operating conditions, members of the Lactobacillaceae family within Firmicutes and the Acetobacteraceae family within Proteobacteria were ubiquitous. Members of the Prevotellaceae family within Bacteroidetes and Lachnospiraceae family within the Clostridiales order of Firmicutes were mostly abundant at 35 degrees C and not abundant in the microbial communities of the TS reactors incubated at 55 degrees C. The ability to adjust bioreactor operating conditions to select for microbial communities with different fermentation product profiles offers new strategies to explore and compare potentially valuable fermentation products from TS and allows industries the flexibility to adapt and switch chemical production based on market prices and demands. (AU)

• FAPESP's process: 18/24360-0 - Integration of downstream technology with fermentation process from complex biorefinery waste
• Grantee: Paula Rúbia Ferreira Rosa
• Support Opportunities: Scholarships abroad - Research